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Parthenogenesis is a mode of asexual reproduction in which offspring are produced by females without the genetic contribution of a male. Among all the sexual vertebrates, the only examples of true parthenogenesis, in which all-female populations reproduce without the involvement of males, are found in squamate reptiles (snakes and lizards). [1]
In species that use the XY sex-determination system, parthenogenetic offspring have two X chromosomes and are female. In species that use the ZW sex-determination system the offspring genotype may be one of ZW (female), [28] [29] ZZ (male), or WW (non-viable in most species, [31] but a fertile, [dubious – discuss] viable female in a few, e.g ...
Females also gain nutrients from sperm storage so the more a female mates with different males the more nutritional access she will obtain. [40] After copulation, some female lizard species chose the sex of their offspring based on the male's sperm. Females produce sons with sperm from larger sires, and daughters from sperm with smaller sires. [41]
The desert grassland whiptail lizard (Aspidoscelis uniparens) is an all-female species of reptiles in North America. It was formerly placed in the genus Cnemidophorus. A common predator of the whiptail lizard is the leopard lizard that preys on A. uniparens by using ambush and stalk hunting tactics. [2] [3] [4] These reptiles reproduce by ...
Cloaca of a red-tailed hawk. A cloaca (/ k l oʊ ˈ eɪ k ə / ⓘ kloh-AY-kə), pl.: cloacae (/ k l oʊ ˈ eɪ s i / kloh-AY-see or / k l oʊ ˈ eɪ k i / kloh-AY-kee), or vent, is the rear orifice that serves as the only opening for the digestive (), reproductive, and urinary tracts (if present) of many vertebrate animals.
The sexual dimorphism in amphibians and reptiles may be reflected in any of the following: anatomy; relative length of tail; relative size of head; overall size as in many species of vipers and lizards; coloration as in many amphibians, snakes, and lizards, as well as in some turtles; an ornament as in many newts and lizards; the presence of ...
Sperm storage organs in the fruit fly Drosophila melanogaster.Female was first mated with GFP-male and then re-mated with RFP-male. Female sperm storage is a biological process and often a type of sexual selection in which sperm cells transferred to a female during mating are temporarily retained within a specific part of the reproductive tract before the oocyte, or egg, is fertilized.
A sex organ, also known as a reproductive organ, is a part of an organism that is involved in sexual reproduction. Sex organs constitute the primary sex characteristics of an organism. Sex organs are responsible for producing and transporting gametes , as well as facilitating fertilization and supporting the development and birth of offspring.